I've been through this before in World of Warcraft when they wanted to do free world transfers and it's a bad deal long term to do it. The server is congested because it is where people chose to congregate to do group content, which is the core of the game itself. Also, considering the fact that only a small percentage of players actually do savage, unless the server in question is like the designated savage stomping grounds the raiding populace will also be smaller. Then when the game goes through it's slow periods you'll be on a barren wasteland with barely anyone around to group with or talk to. It turns into a total lone wolf central and you'll get more socializing done in RF, DF, and PF than locally.
If you don't want to believe me, than just make a character on one of these chosen servers that you can transfer to and pop in a few months after the latest patch. You'll see a night and day difference, believe me.
